Post-consumer scrap film recycling system and process

Abstract

A method for processing a supply of post-consumer scrap linear low density or low density polyethylene film into near-virgin quality blown film product. The method includes tearing the supply of film in a shredder, wherein the surface area of the film is exposed, including delaminating the film. The torn supply of film is washed in a hot water bath including a surfactant. The film is agitated in the bath containing the surfactant wherein contaminants on the film are removed from the film. The washed film is ground into smaller pieces and additional washing of the ground film in a rotating friction washer occurs wherein additional contaminants are removed from the film. The ground film is then dried in a dryer and compacted in a compactor without addition of water into granulated objects of near-virgin quality blown film product.

What is claimed is: 
     
       1. A method for processing a supply of post-consumer scrap linear low density polyethylene film or low density polyethylene film into near-virgin quality blown film product, comprising:
 tearing the supply of post-consumer scrap linear low density polyethylene film or low density polyethylene film in a shredder, wherein surface area of the film is exposed, including delaminating the film; 
 wetting and agitating the torn film in a water bath to remove contaminates from the delaminated film; 
 grinding the wetted, delaminated film into ground film in a grinder to reduce the wetted, delaminated film in size; 
 washing the ground film in at least one washing device to remove additional contaminates from the ground film, wherein the at least one washing device contains hot water; 
 wherein one of the water bath or the at least one washing device includes a surfactant; 
 drying the ground film in at least one dryer into flakes of film containing not more than 10% by weight of water content; and 
 processing the flakes of film into granulated objects of near-virgin quality blown film product in an additional processing apparatus. 
 
     
     
       2. The method of  claim 1 , additionally comprising:
 detecting metal in post-consumer scrap linear low density polyethylene film or low density polyethylene film with a metal detector prior to providing the post-consumer scrap linear low density polyethylene film or low density polyethylene film to the shredder. 
 
     
     
       3. The method of  claim 2 , wherein the metal detector subjects the post-consumer scrap linear low density polyethylene film or low density polyethylene film to a magnetic field to identify ferrous metal, wherein the method additionally comprises:
 removing detected ferrous metal. 
 
     
     
       4. The method of  claim 2 , additionally comprising:
 manually removing detected metal at a manual removal station. 
 
     
     
       5. The method of  claim 1 , additionally comprising:
 detecting a non-film object in the post-consumer scrap linear low density polyethylene film or low density polyethylene film with a detector configured as an X-ray machine. 
 
     
     
       6. The method of  claim 1 , wherein the wetting and agitating step comprises:
 separating high density materials from the delaminated film in a prewash/sink/float tank apparatus. 
 
     
     
       7. The method of  claim 6 , wherein the wetting and agitating step additionally comprises:
 initially wetting the delaminated film received from the shredder with a first washing screw and then conveying the wetted, delaminated film to the prewash/sink/float tank apparatus. 
 
     
     
       8. The method of  claim 1 , wherein the washing step comprises:
 washing the ground film in a first friction washer; and 
 washing the ground film in a first turbo washer. 
 
     
     
       9. The method of  claim 8 , wherein the washing step additionally comprises:
 washing the ground film in a second washing screw located intermediate the first friction washer and the first turbo washer; and 
 washing the ground film in a second friction washer located subsequent to the first turbo washer. 
 
     
     
       10. The method of  claim 1 , wherein the hot water is at least about 140 degrees Fahrenheit, but not more than about 190 degrees Fahrenheit. 
     
     
       11. The method of  claim 1 , wherein the surfactant comprises:
 a detergent; and 
 wherein the surfactant optionally comprises at least one of an oxidizer and a bleaching agent. 
 
     
     
       12. The method of  claim 1 , additionally comprising:
 rinsing the ground film in a second turbo washer subsequent to the at least one washing device. 
 
     
     
       13. The method of  claim 12 , additionally comprising:
 drying the ground film in a first turbo dryer located intermediate the at least one washing device and the second turbo washer to remove moisture from the ground film. 
 
     
     
       14. The method of  claim 1 , additionally comprising:
 further separating contaminates from the ground film and further separating layers of the ground film in a hydrocyclone located subsequent to the at least one washing device. 
 
     
     
       15. The method of  claim 14 , additionally comprising:
 washing the ground film in a third friction washer located intermediate the hydrocyclone and the at least one dryer. 
 
     
     
       16. The method of  claim 1 , wherein the drying step comprises:
 drying the ground film in a second turbo dryer; and 
 drying the ground film in a third turbo dryer. 
 
     
     
       17. The method of  claim 1 , additionally comprising:
 temporarily depositing the flakes of film in a film flake buffer silo after the drying step and the processing step. 
 
     
     
       18. The method of  claim 1 , wherein the processing step comprises:
 heating and further reducing moisture contained in the flakes of film in a plastcompactor that fuses the flakes of film into formations of film; and 
 reducing the formations of film into the granulated objects of near-virgin quality blown film product in a second granulator located subsequent to the plastcompactor. 
 
     
     
       19. The method of  claim 1 , wherein the method is performed in a manner to produce granulated objects of blown film product having a gel count that does not exceed 1,000 gels on a 12 inch by 12 inch square segment. 
     
     
       20. The method of  claim 1 , additionally comprising:
 interconnecting the various elements with a conveyor network comprising at least one of a storage conveyor, an inclines conveyor, a discharge belt, a transport screw, and a pneumatic transport tube. 
 
     
     
       21. A method for processing a supply of post-consumer scrap linear low density polyethylene film or low density polyethylene film into near-virgin quality blown film product, comprising:
 tearing the supply of post-consumer scrap linear low density polyethylene film or low density polyethylene film in a shredder, wherein surface area of the film is exposed, including delaminating the film; 
 wetting delaminated film received from the shredder with a first washing screw; 
 removing contaminates from the delaminated film received from the first washing screw with a prewash/sink/float tank apparatus that separates high density materials from the delaminated film; 
 grinding the wetted, delaminated film into ground film with a grinder to reduce the wetted, delaminated film in size; 
 configured to washing the ground film with a washing device to remove additional contaminates from the ground film, wherein the washing device contains hot water at a temperature of between about 140 degrees Fahrenheit and about 190 degrees Fahrenheit, and wherein the washing device comprises: 
 a first friction washer that receives the ground film from the grinder; 
 a second washing screw located subsequent to the first friction washer; 
 a first turbo washer located subsequent to the second washing screw; and 
 a second friction washer located subsequent to the first turbo washer; 
 wherein one of the first washing screw, the prewash/sink/float tank apparatus, and the washing device includes a surfactant; 
 rinsing the ground film in a second turbo washer located subsequent to the washing device; 
 removing moisture from the ground film in a first turbo dryer located intermediate the washing device and the second turbo washer; 
 further separating contaminates from the ground film and further separating layers of the ground film in a hydrocyclone located subsequent to the first turbo dryer; 
 washing the ground film in a third friction washer located subsequent to the hydrocyclone; 
 dry the ground film into flakes of film containing not more than 10% by weight of water content in at least one additional turbo dryer located subsequent to the third friction washer; 
 heating and further reducing moisture contained in the flakes of film in a plastcompactor located subsequent to the second and third turbo dryers, the plastcompactor that fuses the flakes of film into formations of film; and 
 reducing the formations of film into the granulated objects of near-virgin quality blown film product in a second granulator located subsequent to the plastcompactor.